Emission of ions and charged soot particles by aircraft engines

[摘要] In this article, a model which examines the formation and evolution of chemiionsin anaircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission,electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration atthe exit of the combustor and at the nozzle exit of the engine. It also allows the determinationof the charge of the soot particles. For the engine considered, the upper limit for the ionemission index EI_i is of the order of (2-5) x10¹⁶ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. Theresults also show that most of the soot particles are either positively or negatively charged, theremaining neutral particles representing approximately 20% of the total particles. Acomparison of the model results with the available ground-based experimental data obtainedon the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002)shows an excellent agreement.

[学科分类] 大气科学